Multiplicity adjustments in parallel-group multi-arm trials sharing a control group: Clear guidance is needed

Area of Science:

• Clinical Trials Methodology
• Biostatistics
• Pharmaceutical Research

Background:

• Multi-arm, parallel-group clinical trials offer efficiency in evaluating multiple treatments simultaneously.
• Existing guidance on statistical adjustment for multiple comparisons in trials with a shared control group lacks clarity.
• Controlling for type I error is a key consideration in trial design.

Purpose of the Study:

• To evaluate the necessity of statistical adjustment for multiple comparisons in multi-arm trials with a shared control.
• To argue against a universal requirement for multiplicity adjustment in specific multi-arm trial designs.
• To advocate for clearer guidance from regulatory bodies and scientific journals.

Main Methods:

• Review of current evidence and statistical principles related to multiple comparisons.
• Argumentation based on the distinctness of treatments being compared.
• Analysis of the implications of multiplicity adjustment in shared control trials.

Main Results:

• Statistical adjustment for multiple comparisons is not always required when distinct treatments share a control group.
• Current evidence suggests flexibility in applying multiplicity adjustments in these trial designs.
• The necessity of adjustment depends on the specific research question and trial context.

Conclusions:

• Adjustment for multiplicity should not be a mandatory requirement for all multi-arm, parallel-group trials with a shared control.
• Clearer, context-specific guidance is needed from regulators and journals on when to apply multiplicity adjustments.
• This approach can enhance the efficiency and practicality of multi-arm clinical trial designs.